Idea of new racer-access api

access.js

var racerAccess = require('racer-access');
derby.use(racerAccess);
var store = derby.createStore();

// This is current racer-access api
store.allow('change', 'users', function(docName, changeTo, snapshotData, connectSession) {
  return;
});


// This is an idea of new api
// Actions are the same as it is ('change', 'create', etc), but also can be 'read' action
store.allow('change', 'users', {
  // load runs in async submit hook and load data to use later
  // do we need extra argument here?
  load: function(action, collection, docId, session, origin, next) {
    asyncGetSomeData(function(data) {
      next(null, data);
    })
  };
  // assert runs in sync preValidate hook and actually do the job
  // same arguments for all actions and patterns, that would be more flexible
  assert: function(action, collection, docId, extra, session, origin) {
    if (isProhibited) {
      return 'Error';
    }
    return;
  };
});

// If no need for load function, then short form can be used (only assert):
store.allow('change', 'users', function(action, collection, docId, extra, session, origin) {
  if (isProhibited) {
    return 'Error';
  }
  return;
});

// Example of extra argument
// Actual extra depends on action type
var extra = {
  segments: ['names', '2', 'value'], // segments after docId
  value: {}, // new value
  loadedData: null, // data form load function
  opData: {},
  snapshotData: {},
  // for list insert
  from: 1,
  to: 3,
  howMany: 1
};

// Example of origin argument
var origin = {
  isServer: true,
  isIsomorphic: true
};
/**
 * Isomorphic code - code that runs on server and on client
 * isIsomorphic = true if it`s request from client or if it`s client app router that runs on server
 * We need it because model from client app router on server can be serialized to the client with all data
 * We can distinguish model from client app router on server like this:
 */
app.on('model', function(model) {
  model.socket.stream.isIsomorphic = true;
});


/**
 * A little bit more:
 * We can use ShareJS doc filters to restrict returned fields of document
 * Api here is similar to Mongo projections
 */
store.fields('users', function(collection, docId, session, origin, next) {
  if (isAdmin) {
    // All fields except password and hash
    next({password: false, hash: false});
  } else {
    // Just name field
    next({name: true});
  }
});